Capturing the 'Representative Person' Using Exposure Equations and Input Variable Distributions - 18416

Abstract

Radiological performance assessments (PAs) for radioactive waste employ the concept of future human receptors, or persons potentially exposed to radiation releases. The International Commission on Radiological Protection (ICRP) has defined the 'representative person' as a receptor, to replace the earlier concept of an 'average member of the critical group', for use in individual dose assessments and comparisons to regulatory criteria. A representative person can be assessed in PAs by defining a critical group, which is a relatively highly exposed subpopulation; and then estimating average exposures, doses, and risks for that group. Probabilistic PA models employ probability distributions to characterize uncertainty in exposure characteristics/variables at a scale aligned with contaminant transport and other aspects of the PA model. The concept of a representative person from a critical group, in the context of the first stage of an iterative approach and a probabilistic PA model, is illustrated using a receptor scenario and a set of exposure equations that incorporate probability distributions for input variables. Different scenarios may require different equations and distributions, but the approach taken is broadly generalizable. PA practitioners and regulators may benefit from such a generalizable method, as it may simplify approaches as well as facilitate reviews and comparisons between different PAs. (authors)